Police have launched an investigation into a possible massive leak of data of local credit and debit cards.

Police said on Monday that they seized two external hard drives from a suspect surnamed Lee, who allegedly attempted to hack into the computer network of a local commercial bank last year. 

The seized hard drives reportedly contained a massive amount of credit card data stolen by the suspect, although it's not known yet how much personal and financial data has been leaked.  

Police suspect Lee had accomplices and are expanding the probe, but having difficulties analyzing the data. 

A police official said that police asked the Financial Supervisory Service(FSC) to analyze the data in March, but the FSC has not been cooperative. The official added that police are continuing the probe while seeking cooperation from financial authorities.